I used half leather seats from a Corsa/Astra SRi and they're a nice fit - only £50 the pair, too

The runners are still on them but I removed the box sections from across the floor to get them as low as possible. I'm 5' 10" and there's loads of headroom. The drivers seat is height adjustable as well and actually sits lower than the fixed height passenger seat. They do have tilt forward backs and I had to swop them side to side because the seat belts caught on the levers so the passenger now has the lowest seat
